Mythbusters: Motorcycles pollute more than cars do

03 October 2011

Mythbusters: Motorcycles pollute more than cars do


Mythbusters hosts Adam Savage and Jamie Hyneman are at it again, this time trying to find out if motorcycles pollute less than cars. They certainly use less gasoline, so there is less carbon dioxide emitted—the amount of CO2 created is directly proportional the amount of gas burned. The rest of the comparison does not fall in the motorcycles favor.


Does this mean we should all stop riding? Not quite. Indeed, during a discussion of the show the hosts said “This is more about being thought-provoking than providing a definitive answer to this stuff.” In their test, Adam and Jamie tested motorcycles and cars from the past three decades. Apart from carbon dioxide emissions, motorcycles were drastically worse. In all but one case (1980’s Nitrogen Oxides), the motorcycles produced multiples more carbon monoxide, hydrocarbons, and nitrogen oxides. These are old bikes and cars, however, and so they are all putting out much higher amounts of VOCs and oxides.


In any case, cars and SUVs vastly outnumber motorcycles. About 6 million cars and light trucks are sold every year in the United States, while only about a million motorcycles are sold. There are about 250 million cars registered in the US, and only about 8 million motorcycles. When you take into account that motorcycles have gotten a lot cleaner, that there are far fewer motorcycles than cars, and that they generally cover fewer miles than cars, the damning result of the Mythbusters study doesn’t have quite the bite.


There is also a new EPA regulation that went into effect in 2010; it drastically lowered the acceptable emissions for motorcycles, even though the regulations still haven’t caught up with those of cars. We’d like to see a comparison of, say, a 2012 BMW motorcycle and a BMW car, or a Honda motorcycle and a Honda car. Companies like BMW, Honda, and Suzuki employ their car catalytic converter expertise in their motorcycles and voluntarily beat the minimum emissions requirements.


Not only that, but motorcycles don’t have to troll for parking in urban areas like cars do, aren’t left idling outside of buildings, and don’t get stuck in traffic jams.



It is also worth noting that the various emissions mean different things. Burning less fuel reduces our reliance on foreign oil, and in turn produces less of the nonpoisonous but global-warming causing CO2. The carbon monoxide, nitrous oxides, and hydrocarbons reduce air quality and cause asthma, but part of the reason that these motorcycle emissions seem so high are that new cars are so ridiculously low. Even so, motorcycle manufacturers are making strides in emissions reduction.



We scoured various websites to find some current motorcycle emissions results. Honda posted the fuel economy and emissions information for their latest motorcycles (although we wonder how G/KWH compares to g/mi).  In any case, if you’re looking to reduce dependence on foreign oil, and to reduce greenhouse gas production, motorcycles are still your best bet!



Two quotes from the show:


This is more about being thought-provoking than providing a definitive answer to this stuff because to do this thoroughly you would need to test lots and lots of cars and look at them in different ways. There are engineers that deal with cars who would write a PhD on stuff like this.”


“We looked into cars vs. bikes and the resources they take to build. The broad category, the idea of looking at a figure like this; we can’t measure everything a factory is doing. We tend not try not to represent those figures heavily in the show. The research that we did showed that because bikes are produced in smaller numbers than cars, there are inefficiencies in the manufacturing process that make bikes as or less efficient than cars to manufacturer. That it actually takes more resources to produce motorcycles because they produce so many less of them and they lose the economies of scale.”


See the new EPA regulations here


NYTimes article


Mythbusters bike vs. car discussion video


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